Vacuum breaking valve



Oct. 18, 1938. J. A. BROOKS VACUUM BREAKING VALVE Filed March 4', less /l, 5 V E.

Patented Oct. 18, 1938 UNITED STATES PATENT OFF/ICE 8 Claims.

This invention'relates to valve structures and has particular relation to a valve structure of a vacuum breaking type, the principal objects being the provision of a valve of the type described that is simplein construction, eicient in operation and relatively economical to produce.

Objects of the invention include the provision of a valve structure which will automatically vent the interior of the Valve to the atmosphere upon the occurrence of a suction or partial vacuum in the supply line; the construction of a Valve of the type described wherein the vent is automatically rendered effective each time the valve is closed and is automatically sealed off from the interior of the valve each time the Valve is opened when there is a positive pressure in the supply line; the provision of a Valve of the type described so constructed and arranged as to automatically vent the interior of the valve to the atmosphere when the valve is closed and in which the vent is normally sealed from the atmosphere upon opening of the valve but is so constructed and arranged as to automatically vent the interior of the Valve to the atmosphere when the Valve is open and when a suction or partial pressure occurs in the supply line; the provision of a valve structure in which the valve is opened against the force of the pressure in the supply line and the means for opening the valve is movable independently thereof, the opening means and the valve cooperatingto form a valvular means within the body of the valve controlling the venting of the interior of the valve body to the atmosphere; the provision of a valve structure including a main supply controlling valve and a vent controlling valve, both valves being operated with respect to their seats each time the main valve `is opened and closed; and the provision of a valve structure which will not only Vent the interior of the valve body upon the occurrence of a suction or partial pressure in the supply line but will positively seal oi the interior i of the Valve structure `from the supply line under such circumstances. The above being among the objects of the present invention the same consists in certain novel features of construction and combinations of parts to be hereinafter described with reference to the accompanying drawing, and then claimed, having the above and other objects in view.

In the' accompanying drawing which illustrates suitable embodiments and in which like numerals refer to like parts throughout the several different'views,

5 5 Fig. 1 is a more or less diagrammal@ View illustrating the Valves constructed in accordance with the present invention connected in the water supply lines leading to a closet seat and a wash basin of the type commonly found in bathrooms;

Fig. 2 is an enlarged partially broken vertical 5 sectional View taken axially through'the faucet for thewash basin illustrated in Fig. l;

Fig. 3 is a transverse sectional view taken on the line 3-3 of Fig. 2;

Fig. 4 is an enlarged vertical sectional view l0 taken centrally through the valve shown connected with the toilet seat in Fig. 1;

Fig. 5 is a transverse sectional View taken on the line 5 5 of Fig. 4; and,

Fig. 6 is a fragmentary sectional View of a l5 valve similar to that shownl in Fig. 4 but illustrating a modif-led form of construction for the lower end lof the same.

'I'he danger of cross-connections in plumbing systems is well understood by those skilled in the 20 art and particularly to sanitary engineers. The term cross-connection applied to plumbing fixtures means that by joining the fixture to the supply pipe it makes it possible for liquids, such as household waste, water from lavatories, water v25 closet tanks, sinks and bath tubs and excreta consisting of urine and faeces from water closets and the waste contents of-instruments and utensil sterilizers, bar and soda fountain sinks, glass washers, flush rim floor drains, etc. to be trans- 3o ferred from plumbing fixtures to the water supply pipes. A cross-connection makes possible the transfer of sewage from a plumbing fixture toa water supply pipe by joining or linking the two together. The agency of transfer may be grav- 35 ity or siphonage. The under-rim inlet type of `supply connections makes possible the transfer of sewage, human excreta, body, domestic and other wastes or infectious material from a plumbing y transfer to a water supply system furnishing safe 40 water. In general it may be stated that the danger of a cross-connection causing contamination of a safe water supply is possible Where-the discharge from a valve or other water controlled fitting is submergedin a supply of contaminated 45 water and the valve is opened at a time when the pressure *in the supply line. f'alls below atmos. pheric pressure. Submersion of the discharge end of a Valve or other valve controlled fittings occurs naturally in some plumbing fixtures as, 50 for instance, bottom inlet bath tubs; it occurs as a' result of the stoppage of the drain or the overflow in under-the-rim types of wash basins, bath tubs, many types of toilets and a. great many other types of fixtures; and occurs in any case where a hose, tube or other conduit is attached to the discharge end of a faucet or nozzle and the opposite end of the hose or the like is submerged in a tank, basin, pail or any other open body of water.

Generally speaking, two conditions must occur simultaneously in order to render the possibility of a cross-connection polluting the water supply dangerous, namely (1) water supply pressure failure and emergency shut-off, and (2) stoppage. Water supply pressure failure may occur because of breaking of water mains or services; fluctuation in pressure of the municipal supply from above to below atmospheric pressure; improperly designed or undersized water distributing systems particularly in tall buildings; heavy demands in extended dry periods reducing normal working pressure in city mains; re pumps connected to a fire plug; kturning oif the water supply at the foot of a pipe riser in the event of stoppage; turning off the water in the basement in emergencies; repairs, replacements, leaky pipes or other causes; and many other similar conditions. Stoppages in plumbing' fixtures may be due to accidents, carelessness, abuse or to other causes and there are few if any plumbing fixtures that do not at some time become clogged.

In any event wherever the pressure in a water supply pipe falls below atmospheric pressure and the discharge end of any plumbing fixture is simultaneously submerged in polluted water, unless some means are provided for preventing siphonage of the polluted water back into the water supply system the water supply system will be contaminated. For a more complete discussion of the dangers of cross-connections in plumbing systems reference may be had to the report of the research committee of the American Society of Sanitary Engineers on cross-connections submitted at the 1931 annual meeting of the American Society of Sanitary Engineers at Richmond, Virginia under date'of Sept. 9, 1931.

The present invention provides a novel form of valve structure for use in plumbing systems and by the use of which danger of cross-connections because of siphonage is effectively eliminated. The present invention is based upon the principle that no contamination of a potable water supply can occur by siphonage -ii. air in sufficient quantities is introduced into the high point of the siphon any time that the water pressure on the supply side of the valve falls belor.T the pressure on the discharge side thereof, as in such case the two legs of the siphon are separated by a free body of air which prevents the weight of the water in the long leg of the siphon from exerting any appreciable effect upon the water in the short leg. Accordingly, by use of the present invention a Water control valve is provided including a valve body, a supply control valve and means for moving the valve from its seat, the. valve and its actuating means being relatively movable with respect to each other and vent means for the interior of said valve body being provided. 'Ihe vent means is so constructed and arranged that when the valve is open under any condition in which the pressure in the supply line exceeds the pressure on the discharge side of the nozzle the vent will remain closed when the supply control valve is open, but whilethe supply control valve is open should the pressure in the supply line for any reason or other fall below the pressure of the discharge side of the valve the vent will immediately become effective to vent the interior of the valve body to the atmosphere and thereby and particularly to Fig. 1 a toilet seat is illustrated at I0 and a wash basin at I2. A water supply pipe is indicated at I4 and for the purpose `of illustration in the present case may be considered asbeing connected to a municipal water supply system and, therefore, normally lled with 'a supply of potable water under a material positive pressure. The supply line I4 is connected to the closet I0 by suitable ttings including, in this particular instance, a valve indicated generally at I6 constructed in accordance with the present invention. The supply line I4 is also connected by means of the pipe line I8 with a faucet indicated generally at positioned to supply water to' the wash basin I2, the faucet 20 also being constructed in accordance with the present invention.

As will be appreciated were it not for the special valve I6 any condition of stoppage of the' toilet I0 which would cause the contents of the same to overiiow its rim would endanger contamination of the Water supply in the pipes I4 if the pressure in the pipe I4 fell below atmospheric pressure. That this might readilyoccur will be understood and that the most natural thing to do upon over-running of the toilet I0 would be to shut oif the water supply in the basement whereupon the opening of any valve between the toilet IIJ and the main supply valve which has been shut off would immediately render the sup-v ply pipe I4 the long leg of the siphon and immediately tend to withdraw the contents of the toilet In into the supply pipe I4. Likewise were the faucet 20 an under-the-rim type of faucet and the drain and/or the overflow of the basin I2 stopped up, or where a shampoo head or other tube or hose is fastened to the type of faucet 20 shown and its discharge end submerged in the water in the bowl I2, any reduction of pressure in the supply pipe I4 below atmospheric pressure when the faucet 20 is open would then tend to siphon out the contents of the bowl I2 into the supply pipe I4.

Referring to the faucet 20 illustrated in detail in Figs. 2 and 3 it will be noted that the same includes a valve body 24 having a conventional form of discharge spout 26 and an inlet opening 28 in this case formed with a valve seat 3U at its entrance end which in this case is at its lower edge. A nipple 32 is threadably received by the valve body 24 concentrically of and below the opening 28 and is centrally provided with a spider 34 which centrally receives therein the stem of the main supply valve 36 for axial sliding movement toward and from the valve seat 30. The valve 36 includes a disc 38 of a suitable or conventional type of valve seating material adapted to co-operate with the seat 30 to provide a fluidtight joint. It will be appreciated that water' under pressure in the nipple 32 which in the particular arrangement illustrated in Fig. 1 is connected with the supply pipe I4 through the line I8, is relied upon to maintain the valve 36 in closed position, and in order to open the faucet the valve 36 is forced downwardly against the pressure of the water in the nipple 32 away from the seat 30. In thel particular construction shown in order to move the value 3'6 away from the seat 30 a post-like member 40 is secured to the valve 36 in axially concentric relation with respect thereto and projects upwardly therefrom into the interior of the valve body 24. In the particular case shown the post 40 is provided at its lower end with an annular ange 42 and a stud 44 extending axially therebeyond, the stud 44 passing through the seating material 38 and being threaded into the valve 36 not only to secure the post 46 fixedly with respect thereto but also to ilrmly clamp the seating material 36 in proper position on the valve 36.

In the broader aspects of the present invention the post 40 may be axially actuated to open the valve 36 by any suitable or conventional form of mechanism such as is conventionally employed for operating valves and particularly that type of mechanism employed in connection with valves which are constantly urged towards closing position, but for the purpose of illustration in the present case such means is shown in the form of a stem 46 provided with external threads 48 cooperating with complementarily formed threads in the valve body 24 and positioned in axially concentric relation with respect to the post 40 and valve 36. The stem 46 is adapted to be moved axially upon manual actuation of its handle 50 secured thereto in a conventional manner as by means of the pin 52. A conventional form of packing 54 and packing nut 56 cooperate between the stem 46 and the valve body to prevent leakage of water along the stem 46.-

I'he stem 46 at its ."'er end is provided with a bore 58 in which the upper end of the post 40 is loosely and slidably received. Axially concentric with the bore 58 and extending axially therebeyond to a point `above the upper face of the packing nut 56 is a smaller bore -60 forming a shoulder 62 at its junction with the bore 56 and which shoulder forms the seat of the vent valve.

The vent valve itself is formed by the upper end of the post 40 and cooperates with the seat provided by the shoulder 62 to close the passage 60 to the interior of the valve body 24 as will hereinafter be more fully explained. The contact 50 between the upper end of the post 46 and the valve seat 62 provides the connection between the stem 46 and the post 40 to enable the stem 46 to move the valve 36 from its seat 30. It vwill be appreciated ,that if the handle 50 is rotated to cause movement of the stem 46 axially downwardly as viewed in Fig. 2 the stem 46 in moving downwardly will first bring the valve seat 62 into contact with the upper end oi the post 4I?, and then continued movement of the stem 46 downwardly will act through the stem 40 to force the valve 3601i of the seat 30 and thus open the passage 26 tol the flow of water to the interior of the valve body 24 from the interior of the nipple 32 and discharge of such water from -the spout 26. When the valve is in the thus described open position, if the direction of rotationof the handle 50 is now reversed the stem 46 will be caused to move upwardly and the pressure of the water acting on the valve 36 will cause the valve 36 and-post 40 to follow the upward movement of the stem 46 until the valve 36 becomes seated, thus closing oi! the ,ow of water, and continued upward movement of the stem 46 will disengage the upper end of the post^40 from the seat 62 In accordance with the present invention the passage 60 may be connected to the atmosphere at any desired location above the seat 62 but preferably above the top of the nut 56. In the particular instance shownthis connection to the atmosphere is made by-means of a transverse passage 64 extending through the stem 46 and the hub of the handle 5I). Accordingly, it will be recognized that when the operating parts of the faucet 20 are in the position indicated in Fig. 2 the valve 36 is closed to the ow of water from the interior of the 'nipple 32 to the interior of the valve body and the interior of the valve body is vented to the atmosphere independently of the spout 26 through the passages 64, 60 and through the clearance space between the exterior of the post 4D and the walls of the bore 58, this ventv communicating with the atmosphere above the discharge end of the spout 26 which under some circumstances may in effect be submerged because of the employment of a hose, spray head, or

fact that the upper end ofthe post '40 is at A such times in contact with the seat 62 and, therefore, effectively closes the vent opening to the escape of fluid pressure from within the valve body. On the other hand, while the handle 50 is turned to such position as to force the valve 36 from its seat and the discharge end o! the spout 26 be immersed in a body of polluted water, should the pressure in the supply line lI4 fall below atmospheric pressure the valve 36 will immediately be moved downwardly because of such diilerence in pressure and unseat the upper end of the post 40 from the vent seat 62, immediately venting the interior of the valve body 24 to the atmosphere through the passages 60 and 64 and eifectively destroying any sub-atmospheric pressure tending to siphon contaminated water through the faucet into the supply line I4.

An additional feature of the construction is A that under a condition in which the discharge .end 26 is submerged, for instance as bymeans of a hose or tube projected into a pail of contaminated water or the like located at a point below the'discharge end of the spout 26, when the .handle 50` is moved to permit closing .of the valve 36 under the pressure of the water in the nipple 32 and, therefore, the supply line I4, the moment that the handle is turned beyond the position necessary to eifect sealing of the valve 36, the upper end of the post 4I) will be separated from the valve seat 62, and the interior ofthe valve body 24 being thus vented, immediately permits the contents of the valve body 24 and the supply control valve is closed, it provides a vented valve structure in which the vent is politively closed when the valve is opened against a positive pressure of water in the supply line thus permitting the valve to be employed in constructions in which the interior of the valve body is placed under the same pressure as the water in the supply line during operation; and provides a construction in which when the valve is in open position and sub-atmospheric pressure occurs in the supply line, siphonage between the inlet and outlet ends of the valve is immediately prevented by freely venting the interior of the valve to the atmosphere. Accordingly, a valve constructed in accordance with the present invention provides a safeguard against the contamination of a water supply through cross-connections because of possible siphonage through the valve.

- Referring now to the form of the valve |6 illustrated in detail in Figs. 4 and 5 it will, of course, be understood that this valve is not only applicable in connection with toilet seats as in Fig. 1 but is applicable for use in any plumbing system for controlling the flow of water therethrough. To obtain the benet of the construction in order to prevent any siphonage because of cross-connections and tol guard the possible danger of cross-connections by gravity drainage through the valve, the valve should always be placed at the top of any piping system which might function as a siphon and above the top of any basin, tank, or other open receptacle to which it controls the flow of water. The valve I6 illustrated is particularly adaptable for a greater flow of water therethrough than the faucet 20 and consequently requires provision for a greater amount of venting air, and its proportions are such as to effect this result.

Referring now to Figs. 4 and 5 the valve |6 is shown as being provided with a hollow body 10 the lower end of which is enlarged as at 12 with its terminus internally threaded as at 14 for reception of a suitable pipe, and as being provided with a valve seat 16 at the junction of the enlarged portion 12 with the main body portion 10. An outlet connection 18 is provided in the body 10 above the seat 16. The body 10 is internally provided with a pair of axially spaced spiders 80 between which is axially slidably received the stem 82 of the water supply control valve indicated generally at 84. The valve 84 comprises a supporting cup or disc 86 and a disc 88 of conventional valve seating material, the members 86 and 88 being clamped between the nut 90 threaded on the lower end of the stem 82 and the washer 92 which abuts against the shoulder formed at the junction of the reduced lower end of the stem 82 with the main body portion thereof. The upper end of the stem 82 is enlarged above the upper spider 80 to form an upwardly opening cup 94 in which is received a disc 96 of conventional valve seating material. Contact of the valve 84 with the seat 16 and of the cup 94 with the upper spider 80 limits the axial movement of the valve assembly in the opposite direction.

The upper end of the body 10 is provided with a centrally apertured cap member 98 threaded thereon and sealed thereto by means of a gasket |00. The central aperture in the cap member 98 is threaded for co-operation with the threads |02 formed on the exterior of the hollow handle stem |04. A packing nut |06 and packing |08 provide a water-tight connection between the cap 98 and the stem |04. An operating handle 0 is formed integrally with the upper end of the stem 04 and is hollow, its hollow interior being fully open to the interior of the hollow stem |04 and being open to the atmosphere by means oi openings ||2 formed in the lower face of the handle ||0. The lower end of the stem |04 is preferably beveled off as at |4 so that the lower end of the stem |04 will act as a valve in cooperating with the seating material 96.

The enlarged lower end 12 of the main body portion 10 serves as the inlet connection for the valve and, accordingly, the supply controlling n'alve 84 is normally maintained in contact with the seat 16 to keep the valve in closed position when there is a positive pressure on the supply side of the valve. Turning of the handle ||0 acts through the threads |02 to force the stem |04 downwardly to open the valve 84 against pressure of the water on the supply side, the first or initial movement of the stem |04 acting to bring the lower beveled edge ||4 thereof into sealing relation with respect to the seating material 96 and thereafter to force the valve 84 from the seat 16 to permit a flow of water through the structure, the pressure of the water in the supply line maintaining sealed relation between the edge ||4 and seating material 96 while'there is a positive pressure in the supply line and when the valve is y in open position.

To close the valve when once in open position the handle ||0 is rotated to raise the stem |04 and thus permit the pressure of the water in the supply line to move the valve 84 into contact with the seat 16, further movement of the stem |04 upwardly separating the end ||4 from the seating material 96 and thus freely venting-the interior of the valve body 'to the atmosphere. In this valve, in a manner similar to the valve or faucet previously described, it will be readily understood that any condition tending to reduce the pressure in the inlet 14 below atmospheric pressure will immediately permit the valve 84 to drop away from the seat 16 and immediately place the interior of the valve body and the supply pipe in open communication with the atmosphere, the size of the vent passages in this case being so large that regardless of the intensity of the suction that might occur in the supply line it will be impossible to build up any appreciable suction in the outlet connection 18 to withdraw any liquid back into the interior of the valve body and consequently the supply line through the outlet connection. Likewise should the valve 84 be closed at any time that the pressure in the supply line falls below atmospheric pressure, the valve 84 will immediately drop away from the seat 16 and similarly freely vent the interior of the supply line to the atmosphere.

One feature of the valve construction in accordance with the present invention is in connection with the drainage of the discharge line extending therefrom. For instance where a hose or the like is connected with the discharge nipple 18 of the valve shown in Figs. 4 and 5, immediately upon seating of the valve 84 a slight continued rotation of the' handle ||0 in a closing direction raises the end I4 of the stem |04 from the valve seating material 96 and vents the interior of the valve body to the atmosphere. This venting then permits any water or other liquid in the discharge line from the valve to drain by gravity from the line. It will be appreciated that this is of advantage in many instances. It is particularly advantageous in connection with lawn sprinkling systems as more fully brought out in my copending application for Letters Patent of the connection with lawn sprinkling systems is that under some circumstances pools of water contaminated by fertilizers of diierent characters or poisons applied to a lawn to control insects or the like may accumulate over one or more of the sprinkler heads and if the various lines of pipes constituting the sprinkler system are not permitted to freely drain by gravity the danger of pollution of the water supply line is greatly increased.

The safety feature of the present valve construction in its application to the control of lawn sprinkling systems may be increased in the manner illustrated in Fig. 6 wherein the supply controlling valve is provided with a second seat which becomes effective upon reduction in pressure in the supply line to less than atmospheric to positively seal the supply line against reversal of ow at the valve. Referring to Fig. 6 it will be noted that this modification includes the provision of a second valve seat 16' which is threadably inserted into the enlarged lower end 12 of the valve body 10 so as to be positioned in opposed and axially spaced relation with respect to the valve seat '16. 'I'he control valve 84' in this case is modified to provide an additional disc 88( of valve seating material on its lower face for cooperation with the seat 16', the lower end of the stem 82 being sufficiently elongated to accommodate this added thickness of the valve 84. This modified construction will operate very similar to the construction shown in Fig. 4 except that upon reduction in pressure of the water in the supply line to the valve to less than atmospheric pressure the valve 84' will immediately drop upon the seat 16', whether it is in open or closed position, and positively seal off the interior of the supply line to a reverse flow. At the same time this action freely vents the interior of the valve body and consequently the outlet connection 'I8 and any line connected thereto to the atmosphere. While the construction shown in Fig. 6 may be desirable in connection with lawn sprinkling systems for the reasons heretofore stated it generally is not desirable in connection with the various xtures in a building for the reason that it will act to prevent complete drainage of the supply line connected thereto.

Formal changes may be made in the'specic embodiments of the invention described without departing from the spirit or substance of the broad invention, the scope of which is commensurate with the appended claims.

What I claim is:

1- In a valve structure, in combination, a body having an inlet and an outlet, a valve seat formed between said inlet and outlet, a valve on the inlet s ide of said valve seat cooperable therewith to control the ow of fluid through said body, means for guiding said valve for movement toward and from said seat, said valve being unrestricted in its movement toward and from said s eat in response to fluid pressure acting thereon. manually controllable means supported by said body movable toward and from said valve seat', means slidably associated with said manually controllable means interposed between said manually controllable means and said valve whereby to enableisaid manually controllable means to be operated to move said valve `away from said seat, said manually controllable means being provided with an air vent therein communicating the interior of said valve body with the atmosphere exterior thereto and the second mentioned means cooperating with said manually controllable means to provide a valve for said duct, the last mentioned means and said manu- 5 ally controllable means being so constructed and arranged that movement of said valve away from said seat when said manually controllable means is in valve opening position automatically opens said vent to the passage of air therethrough to the interior of said valve body. l Y

2. A valve structure comprising, in combination, a valve body having an inlet and an outlet, a valve seat formed between said inlet and outlet, a valve cooperable with said seat and adapted to be constantly urged towards seated position l with respect: thereto only by fluidunder positive pressure in the inlet, means associated with ,said body movable toward and away from said valve for normally controlling the position of said valve with respect to said seat, said valve structure being provided with a vent passage communicating the interior of said body with theexterior thereof, said means forming a valve part for controlling said vent passage, said parts being so constructed and arranged that movement of said valve away from said seat independently of said means renders said vent passage effective for the purpose of venting air to the interior of said valve body, and movement of said means to move said valve from said seat against a positive pressure in said inlet renders said means effective to close said vent passage.

3. In a valve structure, in combination, a valve body having an inlet and an outlet, a valve seat between said inlet and outlet, a valve device within said body including a part cooperable with said seat to interrupt the ow through said body between said inlet and said outlet and including a second valve forming part, said valve being movable toward said seat only by a differential of fluid pressureacting on opposite faces thereof, means associated with said body and movable toward and away from said valve part cooperable with said valve device to move said valve from said seat and providing a second valve part cooperable with the rst mentioned valve part, and means forming a vent passage closable by cooperation of said valve parts, said parts being so constructed and arranged that movement of said valve device away from said seat without a corresponding-movement of said means automatically effects relative movement between said valve parts to render said passage open for the purpose of venting air to the interior of said body.

4. A valve structure comprising, in combination, a body part providing an inlet and an out- -let, a valve seat formed between said inlet and said outlet, a valve device including a head cooperable with said seat to close said body part to the flow of fluid between said inlet and said outlet, a hollow stem associated with said body part the interior of which is constantly open to the atmosphere, said stem being movable toward and from said valve device and being cooperable therewith to force said head from said seat, said valve device cooperating with said hollow stem to control communication betweenthe interior of said hollow stem and the interior of said body part, said cooperation being such that movement of said valve device in a direction to move said head-away from said seat, without a corresponding movement of said stem, opens said stem to the free passage of air therethrough to 7 the interior of said body part, and said valve device being movable toward said seat only in response to iiuid pressure acting thereon.

5. In a valve structure, in combination, a valve body providing an inlet and an outlet, a seat v'fixed with respect to said body between said in- "let and said outlet, a valve cooperating with Jsaid seat to control the iiow of fluid through said valve body between said inlet and said outlet and movable toward said seat solely in response to fluid pressure acting thereon, means associated with and movable directly with said` lment of said Valve from said seat without a corresponding movement of said stem affects separation of said valve part and said stem and renders said vent passage effective for the purpose of permitting a flow of air through said vent passage into said valve body.

6. In a valve structure, in combination, a Valve body providing an inlet and an outlet, a valve seat between said inlet and said outlet, a valve associated with said seat and movable toward said seat solely in response to fluid pressure acting thereon, a valve seat carried by said valve, a hollow operating stem associated with said body and movable toward and away from the iirst mentioned valve seat, the interior of said hollow stem being open to the atmosphere exterior of said body and an end of said stem cooperating with said second valve seat to close communication through said stem between the interior of said valve body 'and the atmosphere therethrough, said communication being rendered ineffective when said stem is in contact with said second valve seat and being rendered eiective when separated therefrom.

7. In a valve structure, in combination, a valve body having an inlet and an outlet, a valve seat in said body between said inlet and said outlet, a valve associated with said seat for controlling the flow of fluid therethrough and movable toward said seat solely in response to fluid pressure acting thereon, a post secured to said valve and movable therewith, a stem movable toward and from said seat, said stem providing a vent passage therein connecting the interior of said valve body with the atmosphere exterior thereto, a shoulder formed in said vent passage, said post cooperable with said shoulder to render said vent passage inoperative when in contact therewith and to render it operative when sepa- 'gated therefrom, said stem cooperating with said post through said shoulder to enable movement of said stem toward said seat to move said valve from said seat, said post automatically separating from said shoulder upon movement of said valve away from said seat independently of a corresponding movement of said stem.

8. In a valve structure, in combination, a valve body providing an inlet and an outlet, a pair of axially spaced valve seats within said body between said inlet and saidoutlet, a valve positioned between said valve seats and movable therebetween into contact with either one thereof to interrupt the flow of i'luid through said body between said inlet and said outlet, means associated with said valve providing a valve part, a stem movable toward and from said valve seats cooperable with said valve part to move said valve from one of the rst mentioned seats, and said stem forming a second valve part cooperating with the rst mentioned valve part' to providev valvular means controlling the venting oi the interior of said valve part to the atmosphere independently of said inlet and said outlet.

JOHN A. BROOKS. 

